thedarkshade

Well that's different from what we learned at school. Let's refer to this equation that I learned at school and that is for friction force: F=Nµ (N=Q=mg) /:N µ=F/N So by this second equation we can clearly see that with the increase in friction force, we also increase the friction coefficient!

It's kinda creepy what you're saying! Friction after all is a fore that acts against the movement! This is why objects won't move infinitely when a force acts on them only once! And if you take a more logical approach to this, you'll see that what you're saying actually makes no sense! Think about Newton's third law. The action force is equal to reaction force. So with the increase in the force that makes the object move, the fiction force must increase too so the coefficient increases!

I think it's rotation too. Because if you throw the ball rotating horizontally in a 180(scale) angle, then it's destination will change from it's primitive direction. But on the other hand you make that rotations possible by throwing it!

Let me make this simplier! At school we did a very simple experiment! We used different materials and placed them at different angles! The higher the angle, the bigger the friction coefficient, and all the materials started falling down! And all the results were generally the same! With the increase on the friction coefficient each material started to move! That's why kinetic friction coefficient is bigger than static one! Of course different materials had different numerical values but they all started moving with high friction coefficient! You can try that experiment too if you want, I'll give you the formula, just let me know!

I think it's the other way around actually! The coefficient of kinetic friction is BIGGER than static friction. Because with the increase on friction coefficient the body starts moving. The bigger the coefficient the faster movement!

My definition of force is "a change in inertial state"! Because bodies are in inertial state when nothing acts on them, so a change on that state is actually a force! And yet an easier definition of force (on a book I've read) is "force is a push or a pull"! And they're physicists who wrote that!

How could "that energy" not be inserted uniformally when there was nothing that could prevent this energy be inserted uniformally? Before universe and now outside universe there is a matterless friction state!

We were discussing about magnesium last class and its reactions with water. And what I found interesting is that when the water is cold, it forms magnesium oxide, but when the water is hot (near boiling temperature) then it forms magnesium hydroxide. These are the reactions: Mg + H20 --> MgO +H2 (cold water) Mg + 2H2O --> Mg(OH)2 + H2 (hot water) Interesting! WHY DOES THIS HAPPEN? WHAT CAUSES IT?

Thnx iNow, that really helped!

Yeah, huh dummy huh!!! . thnx

I know they have mass and that their mass is 1836 smaller than proton's mass, but I'm very sure that I heard (in a science video) saying "electrons move at the full speed of light", in some particular occasion! I'll get you the link as soon as I find it!

How come it's done that way???

No, neither is accelerating or decelerating! They'll just keep moving maintaining the same distance from each other (of course, as long as the velocity is constant!)

Even bodies without rest mass can't reach the speed of light, can they? What about when a star's core runs out of hydrogen? And then what about neutron stars? I think I've, in these cases the electrons orbit at THE FULL SPEED OF LIGHT! Possible???

I think what we have to deal with here is called "active transport" (at least we call it that way!) When our muscles are in rest, the level of Na is 10 times bigger outside than inside, and the level of K is 10 times bigger inside than outside. So according to physical laws, Na must move in inside until the balance is reached, and also K must move outside until the balanced is reached too. But here is a specific case that act some stuff called "Na and K pomps". Na pomp prevents Na to enter inside, and K pomp prevents K to go outside. So it acts from the place with less concentration to a place with higher concentration, and of course this does not occur spontaneously so energy is needed. And this energy is ATP (adenozim tria-phosphate), and it consumes quiet a lot energy. 20% of our entire body energy is consumed only by this "active transport" It is also called active process because despite diffusion and osmosis (which need no energy), this needs energy to happen!

It's hard to follow! Could you explain better your question please?

I know this might look silly to some people in here (as there are lots of more important subjects to discuss) what I'm gonna ask, but I really need to figure out how these things work! We've been dealing with some complicated (for me:doh: ) equations lately (like H2O2+KMnO4+H2SO4--> ...), and I just can't figure out how to equalize them using oxidation numbers (as our professor said it is easy to equalize by using oxidation number when the equations are tricky). Could anyone please use any examples of equalizing equations using oxidation numbers and explain them?! I really got to learn them!!! Ooooh, come guys, this thing is really important to me! Any hint would be just fine! Pleasee! for example this equation. 5H2O2 + 2KMnO4 + 3H2SO4--> K2SO4 + 2MnSO4 +O2 + 8H2O I know that both sides now are equal, but I just want to know to know how can we do this by using oxidation numbers! I'm very interested to know. Any clue??

And as the others said, the shadow with the true shape of the leaf will be if the leaf is on the ground, and the shadow will continue fuzz if the leaf is above the ground. This is because as light bends near sharp edges and that bend will go on and will be more apparent if the distance of the leaf (in this case) from the ground is higher, making so the shadow of the leaf less like the true form of the leaf.

I think that there are quiet e few factors that influence on a persons' personality and we all got to admit that no matter if people belong or not the same social class the difference between them is big. Different IQs, different marks, different interests, different hobbies are some things that make people differ from each other. I also agree that genetic informations is the regulator of everything in our organism, so our mental capacities too. After all, I guess they're God's design. But these mental capacities have to be developed in a proper way, otherwise these capacities will gradually become impotent (talent fades away), so the level of education matter too, because after all this is the stage when intellectual skills show up. But another very important factor is also interest. Some people are interested more in exact sciences and some other in fine arts, while some other in social sciences. And people who are interested in art, it's hard for them to cope scientific theories and physical laws and other things related to science. Even if you get Eduard Witter to lecture them physics they will still not understand a damn think about physics and the other thing around too. I do agree with you blue_cristal that genetic code, upbringing and educational level are the three key factors that influence ones intellectual capacities. But putting a percentage between these two would be quiet hard, because different percentages of these three give different kind of people with different mental capacities.

Thanks a lot insane_alien. I was discussing with a friend of mine about metallic and ionic bonds and he started to get a little freaky about it. Sodium is malleable because of metallic bonds (thnx!), but this malleability causes only dislocation of structural nets, giving them the shape we want, but still these metallic bonds don't get "cut off", they still remain, right? My friend is quiet sure that they break.

We've been having few lessons and experiments at school that have to do with alkali metals. Those HUGE explosions (especially K and Cs) in reacting with water make you think about them. But there are a few things I can't figure out, and I'd appreciate any help possible in my following questions? 1. Why are alkali metals so reactive? 2. Why can't you touch Na with uncovered hand? 3.Why metallic sodium (Na) is soft and malleable, while NaCl is strong and frail? I's REALLY appreciate some answers.

Sorry swansont, I mixed it up with the place where the first atomic test took place. I'm very very sure that it was said "10 time higher than normal", and it was Brian Greene who said that on a collection of videos of his Elegant Universe in youtube.

except anything that has to do with our physical reality! Yeah, but it's OK only because those "conditions" are normal because it's light itself.

And this increase in reactivity is due to less nucleus influence on the outer electrons, right? Because going down the groups the number of electrons keeps increasing and also new shells are added, so the distance of the outer electrons from nucleus is also increased! So the nucleus influence on these electrons keeps decreasing down the group, and they become more reactive and less stable, right?

Helium is an inter gas, so it needs extreme conditions to make it react. That is because its electronic configuration is completed (1s^2) and it normally doesn't react. Also the necessary energy to "take" an electron away from helium is huge, energy which reactions cannot provide, so it's normally stable element.